Download Human_Impacts_on_the_Environment

Human
Impacts on
the
Environment
Environmental Science
Pollution–any environmental contaminant that
causes damage or harm
air
water
land
Types of pollutants
• Chemical– car exhaust, oil, smoke stacks,
pesticides
• Solid– litter, trash, soot, plastic
• Biological– sewage, decaying material
• Thermal– excess heat in an aquatic habitat
harms the ecosystem
• Radiation– radioactive waste
Overpopulation
Effects
• Overuse/misuse of
resources
• Encroachment on natural
habitats
• Increased pollution
• Failed infrastructure
One major cause is lack of education.
Earth’s human population in 2013– 7 billion
Estimated carrying capacity 4-16 billion
Habitat Destruction
• First bullet point here
• Second bullet point here
Pollution
Encroachment
Overuse
Group D
• Third bullet point here
Deforestation
Approximately 18 million acres
are lost each year
Reasons
• timber harvest
• commercial or residential
development
• create farmland
Effects
• loss of biodiversity
• loss of rare or currently unknown
species
• increased erosion
• Increased carbon dioxide in
atmosphere
Desertification
Drought is a natural
cause
Humans contribute by
allowing overgrazing and
irresponsible farming
Erosion by wind and
water are the most
significant effects
Biodiversity–
the number and
variety of species
in an ecosystem
Biodiverse
ecosystems are
healthier
Anything that threatens
biodiversity, causing
species to become
threatened, endangered,
or extinct, weakens the
ecosystem.
Threatened Species
The species’ numbers are in
decline, and the species is
likely to become endangered.
Endangered
species
The numbers are so low that
the species is likely to become
extinct without immediate
protective measures
Extinction– if a
species has not been
present in 50 years
Chinese river dolphin
Stephen’s Island wren
Dodo
Root-spine palm
Biodiversity
• Ecosystems are
interconnected in many
ways (it’s not always
obvious)
• Biodiversity increases
Humans benefit from
biodiversity through
• Medicines
• Agriculture
• Industry
sustainability
How many species have become extinct before they were even discovered?
How much biodiversity has been lost, while still unknown?
Modern impact of humans on environment
began during the industrial revolution
• Drastic increase in use of fossil fuels (coal, oil,
natural gas)
• Land damage from mining those fossil fuels
• Rapid urbanization (led to pollution, waste,
lack of infrastructure, diseases)
• 200+ years of pollution (air, land, and water)
• Extreme increase in greenhouse gas
emissions
Individuals can evaluate their own carbon
footprint– a measure (in pounds) of each
person, group, or company’s emissions of
greenhouse gases
• Anything that uses electricity–
heating/cooling, household
lighting, electronics
• Using your car
• Waste products
Conservation
&
Sustainability
Individual or group
efforts to preserve or
protect the
environment–
biodiversity & natural
resources
• Prevent pollution
• Recycling
• Reduce carbon footprint
• Limit consumption
• Limit waste
• Reduce use of fossil fuels
Early 1900s– Theodore Roosevelt enacted the
American Antiquities Act (established National Parks
& other preserved wildlife areas)
1936– National Wildlife Federation founded
1962—Rachel Carson publishes Silent Spring
1963– Clean Air Act
1965– Water Quality Act
1970– First Earth Day
1972- Clean Water Act
1980– Superfund
1990-National Environmental Education Act
2001– U.S. rejects Kyoto Protocol (emissions control)
Partial History of
Environmentalism
in the US
Are atmospheric carbon dioxide
levels rising?
Is Earth’s average temperature
increasing enough to cause a
difference?
Is this a naturally-occurring
phenomenon?
Is this a catastrophe that humans
have caused?
Climate change–
the big debate
Shrinking glaciers
Loss of sea ice
Rising sea level
Longer, more severe heat
waves & droughts
• Increased risk of fires &
floods
• Stronger storms
• Change in weather patterns
•
•
•
•
Effects of
climate change